Field of Invention
The present invention relates to a door locking device for a truck, and more particularly, to a device that is capable of preventing a door from being damaged and a user from being injured by automatically locking the door when a cab of the truck is tilted.
Description of Related Art
In general, in a cab tilting structure for a truck, a chassis and a cab are connected to each other, vibration transmitted from the chassis during a drive is absorbed to control the movement of the cab such that ride comfort is determined and the cab is tilted when servicing is performed.
For example, in a medium and large size truck, main devices for a vehicle, such as an engine and a transmission, are placed at a lower part of the cab. Thus, when servicing is performed, the cab is tilted in a forward direction of the vehicle due to an action of a hydraulic cylinder.
In medium and large sized trucks, the cab is supported by four air springs so as to improve ride comfort. Thus, a cushion action caused by a vertical movement of the springs is always applied to the cab during the drive.
A door for the medium and large size truck is configured in such a way that a key lever ascends and descends due to an acting force of a latch actuator and a key load and locking/unlocking operations can be performed.
For example, as illustrated in FIGS. 7A and 7B, locking/unlocking of a door is performed as a key lever 110 ascends and descends due to an acting force of a latch actuator and a key load 100.
That is, when the key lever 110 ascends, a door-unlocked state is established, and when the key lever 110 descends, a door-locked state is established.
However, current cars are not equipped with an additional safety device that prevents doors from being opened after cab tilting. Thus, there is a high risk that the cab will be damaged by door free drop and a user will be injured when the door is opened after cab tilting due to a user's carelessness.
That is, since the door can be opened in a cab tilted state, there is a high risk that the door will freely drop by its own weight when the door is opened after cab tilting is performed, the cab will be damaged and the user will be injured due to a user's carelessness.
In this consideration, Japanese Patent Application Publication No. 2003-320851 and Korean Patent Application Publication No. 2003-50270, and Japanese Patent Application Publication No. 1998-30371 disclose safety devices relating to locking/unlocking of a door. However, no safety device relating to a cab tilted state has been proposed.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.